An exhaust-heat recovery apparatus recovering heat of exhaust gas of an internal combustion engine is used. For example, exhaust gas evaporates heat carrier such as H2O. And, steam generated by the evaporation is used for warming-up. The steam used for the warming-up is condensed and is circulated in a passage. For example, Patent Document 1 discloses a technology in which it is determined as abnormal when a temperature does not increase within a predetermined time. Patent Document 2 discloses a technology in which abnormality of a valve in a circulation passage is detected based on thermal amount conducted to coolant water from an exhaust-heat recovery apparatus. Patent Document 3 discloses a technology in which abnormality of a thermostat is determined based on a temperature of coolant water after termination of starting of an internal combustion engine.